package com.juc.unsafe;

import java.util.HashSet;
import java.util.Set;
import java.util.UUID;

/**
 * 解决方案
 * 1、Set<String> set = new HashSet<>();
 * 2、Set<String> set = Collections.synchronizedSet(new HashSet<>());
 * 3、Set<String> set = new CopyOnWriteArraySet<>();
 */
public class SetTest {
    public static void main(String[] args) {

        Set<String> set = new HashSet<>();

        //Set<String> set = new CopyOnWriteArraySet<>();
        for (int i = 1; i <= 30; i++) {
            new Thread(() -> {
                set.add(UUID.randomUUID().toString().substring(0, 5));
                System.out.println(set);
            }, String.valueOf(i)).start();
        }
    }
}
